Every proxy keeps its figures in its workspace, but reading them meant
opening JSON files one proxy at a time, and the /stats page starts from
zero with each restart. `stats` reads all workspaces, jails included,
and shows how much of the saving is tool definitions rather than
compression, how many calls ran past the size where /clear pays more,
and when each weekly limit runs out at the current pace.
Switching accounts moves the whole profile, which is wrong when one
account is out of limit and the other lacks its plugins and settings.
`borrow` lends one account's login into another's profile for a while.
The old helper did this and failed twice: an abort left the swap half
done, and a token refreshed in one copy broke the other. Here the
profile's own login is written to a journal before anything changes,
the lent credentials file is a link to the lender's, and `return` puts
everything back from the journal, by hand or from a systemd timer.
Profiles that jails run in are refused unless asked for, since the
login decides whose account customer data goes out under, and status
reports a borrow whose timer was lost.
nvrl